13.5.6 MTIM16 modulo register low (MTIM_MODL)A value of 0x0000 in MODH:MODL puts the MTIM16 in free-running mode. Writing toeither MODH or MODL latches the value into a buffer and the latched buffers areupdated after the second byte writing. The updated values take effect and reload to theMODH:MODL registers in the next MITIM16 counter cycle, except for the first writingof modulo after a chip reset or in BDM mode. However, after a software reset, theMODH:MODL takes effect at once even if it did not take effect before the reset. On thefirst writing of MODH:MODL after chip reset, the counter is reset and the modulo takeseffect immediately. The latching mechanism may be manually reset by setting the TRSTbit of the SC register (whether BDM is active or not).When BDM is active, the coherency mechanism is frozen so that the buffer latchesremain in the state they were in when the BDM became active, even if one or both halvesof the modulo register are written while BDM is active. Any writing to the moduloregisters bypasses the buffer latches and writes directly to the modulo register whileBDM is active, and also the counter is cleared at the same time.Reading MODH:MODL returns the modulo values that are taking effect whenever innormal run mode or in BDM mode.Address: 8h base + 5h offset = DhBit 7 6 5 4 3 2 1 0Read MODLWriteReset 0 0 0 0 0 0 0 0MTIM_MODL field descriptionsField DescriptionMODL MTIM16 modulo (low byte)These 8 read/write bits contain the modulo low byte value used to reset the counter and set TOF. Resetsets the register to 0x00.13.6 Functional DescriptionThe MTIM16 is composed of a main 16-bit up-counter with 16-bit modulo register, aclock source selector, and a prescaler block with nine selectable values. The module alsocontains software selectable interrupt logic.Functional DescriptionMC9S08SU16 Reference Manual, Rev. 5, 4/2017214 NXP Semiconductors
